A permanent magnet motor back electromotive force load measuring method and device

The present invention discloses a permanent magnet motor back electromotive force load measuring method and apparatus using the permanent magnet motor drive control, the permanent magnet motor speed was raised over a given rotational speed of the permanent after a sudden power motor coasts to stop; then the mutual inductance and a voltage measuring device for measuring voltage and frequency of permanent magnet motor, the voltage reaches the rated point when the data acquisition permanent magnet motor voltage and frequency by a voltage measuring instrument, a permanent magnet motor voltage data that is the counter electromotive force measured by load. The permanent magnet motor load measuring means comprises a counter electromotive drive, circuit breaker switch, and a voltage measuring instrument voltage transformer. The present invention is a single stop by measuring the permanent magnet motor over a given rotational speed from the free, using a voltage measuring device for measuring voltage and frequency of the motor speed reduced to rated speed, no load can be measured counter electromotive force permanent magnet motor. The present invention reduces the detection conditions, simplifies the traditional measurement method, and to ensure the reliability of measurement data.